Electrode furnace roof



Nov. 19, 1935. A. MOPHERSON 2,021,424

ELECTRODE FURNACE ROOF Filed Jan. 31, 1935 Patented Nov. 19, 1935 UNITED STATES PATENT, OFFICE ARIA v ELECTRODE FURNACE B001" Howard A. McPherson, Huntington Park, can, assignor to American Manganese Steel '00., U Chicago Heights, 11]., a corporation of Maine Application January 31, 1985, SerialNo. 4,882

1': Claims. (Cl. ass-is) This invention relates to electrode furnaces, and refers more particularly to furnace roofs having a central portion, usually flat, through which the electrodes pass, and a surrounding portion which may be of arch construction.

In the past furnace roofs have sometimes been built of arch formation throughout; but, especially for furnaces in which the electrodes are inserted through the roof, 0. different central structure is preferred. It has been proposed heretofore to make this central structure fiat on top, but where this was done numerous specially shaped bricks were necessary. Furthermore, there has been no roof having electrode openings which has been satisfactory in all respects; One common difiiculty is buckling, crushing or separation of the bricks under expansion and contraction of the various bricks due to the heat of the furnace, there being no proper provision for letting the structure adjust itself to such changes.

According to the preferred formof the present invention which has been chosen for illustration, the central portion of the" roof is made up of only three different forms of brick or blocks and the lines of cleavage are for the most part continuous and are so positioned that the pressure of the arch is satisfactorily distributed among all of the bricks in spite of expansion or contraction due to heat, the lines of cleavage permitting slippage of the various bricks to accommodate such expansion or contraction.

Although only three different shapes of brick are used, all three shapes are used with one or the other side up according to the position of the brick, so that the effect of six different shapes is secured with only three shapes. The use of bricks with either of their opposite sides up is possible because the bricks are not tapered and the omission of the taper is possible because of the satisfactory distribution of the arch pressure among all the bricks, already mentioned. It is obvious therefore that in addition to forming a thoroughly satisfactory structure the new roof is very economical in cost and is relatively simple to build.

In addition to utilizing three reversible bricks to provide six different characteristic blocks multiplied in suflicient numbers to provide the composite roof structure already alluded to, the present invention further contemplates a roof structure composed of segments substantially meeting at the vertical axis of the roof having the sides of such segments defined by vertical planes diverging from said axis; having one or segment composite in structure and made up of triangular blocks, preferably the characteristic bricks herein identified, disposed with vertical side faces radial to the electrode opening and base faces presented in position to abut the bricks or blocks of adjacent segments or abut 105 against special abutment members embodied in the bases of the segments or against surrounding masonry of the furnace.

- with these and various other objects in view, the invention may consist of certain novel fea- 15 tures of construction and operation, as will be more fully described and particularly pointed out in the specification, drawing and claims appended hereto.

In the drawing, which illustrates an embodi- 20 ment of the device, and wherein like reference characters are used to designate like parts,

Figure 1 is a plan view of the roof as a whole; Figure 2 is a sectional view taken approximately through the line 2a:-2:r of Figure 1;

and

Figures 3, 4, and 5 are perspective views of the three bricks used in the central portion of the roof.

Although my invention may take numerous forms, only one has been chosen for illustration. According to this form of the invention all of the roof except the central portion may be built in accordance with prior practice, one satisfactory form being illustrated. In this form there is a peripheral course of bricks l commonly called skew backs, and a. plurality of courses of arch-forming blocks or bricks 2 which may havedifierent shapes, such as those illustrated.

Within the inner annular course of arch-forming bricks is the central portion or roof top to which this inventionmore directly relates. This central portion is subdivided into segmental areas A, B, and C defined by vertical side faces D, E, and F radiating from the center G of the roof; each area being provided with an electrode opening H, J, or K radially remote from the center G; and each segmentalarea being composed of the characteristic bricks herein referred to, namely triangular bricks I and 4, with side faces 5 in vertical planes and radiating from the electrode opening, and having their base faces presented in position to abut either the units of adjacent segments or the special abutment bricks I which complete the segments, or against surrounding arch-forming bricks I. The bricks of three shapes affording six characteristic units, numbered 3, 4, and are illustrated in Figures 3, 4, and 5. The bricks on segment C of Figure 1 have been numbered to indicate the positions assumed by the bricks of the three different shapes, it being readily seen that the positions are similar in the remainder of the roof. At the very bottom of the central portion of the roof as seen in Figure 1, appear two bricks, both numbered 4, but which appear to be somewhat different in shape. These bricks, however, are of identical shape, except that one is inverted with respect to the other. Considering these two bricks, the one on the left is positioned with that side uppermost which is lowermost on the brick on the right. This same explanation applies to the blocks numbered 3. In fact, in the series numbered in Figure 1 every other one is placed with that side uppermost which is lowermost in the intermediate ones. Likewise, the same explanation applies to the blocks 5. In each pair of blocks 5 the two blocks are placed with opposite sides up.

with this arrangement, it is seen that there are numerous lines of cleavage or slippage, the principal ones probably being the radial lines of which six extend from the center to the rim, three of these passing right through the three electrode openings. There are also six lines of cleavage forming complete chords of thestructure under consideration. All six of these pass through the electrode openings. It may be noted that these six chords are in two groups, each group forming an equilateral triangle, the two superimposed groups forming a six-pointed star. The radial lines previously discussed lie midway between the points, thereby separating them one from the other. The structure therefore presents a six-pointed star formatid'n, the six points being evenly spaced and separated from one another by lines of cleavage extending to the center, thus forming an arrangement for perfect distribution of the pressure of the arch. On the outside of each point are blocks 4 and 5 which transmit pressure between the inner row of arch bricks 2 and the star structure described.

The bricks 3 are so arranged around each elec- I trode opening as to accommodate expansion and contraction, while at the same time substantially maintaining the shape of the opening. Nearly all the lines of cleavage between the bricks 3 coincide with other lines of cleavage, so that there is a continuity of the cleavage lines wherever necessary. The bricks I around a given electrode opening which are not separated by a line of cleavage coinciding with another line of cleavage are those bricks which lie adjacent to the shortest chord passing through the electrode opening in question. Because of the closeness of this chord to the edge of the structure under consideration, and .because of the shortness of the chord, a continuation of the line of cleavage is not necessary.

It may be pointed out also that the six radial lines of cleavage divide the structure into six segments of a circle or, in other words, six wedgeshaped sections all pressed equally toward the center. Being wedge-shaped it follows that the pressure toward the center exerted by the arch places the entire wedge member under lateral pressure as well. It follows that every brick in the roof top illustrated is under pressure from three sides. This pressure is great enough to hold the bricks in place by friction so it is not necessary to make them wedged or T-shaped. It should be noted also that each electrode opening is formed of an encircling arch by which is meant that it is completely surrounded by wedge shaped bricks having the point of the wedge directed radially toward the opening, thereby preventing these openings from being weak spots in the roof structure.

The brick used would normally be some form of fire brick, but the term is not used to designate any particular brick composition, since blocks of any natural or prepared material which will stand up under the heat and pressure of the furnace operation, may be used.

It is to be understood that many other embodiments of the invention, including some in improved form, will be apparent, and in the course of time more will be devised by those skilled in the art. It is not desired that this invention be limited to the details described, for its scope includes all such forms or improvements as come within the spirit of the following claims, construed as broadly as the prior art will permit.

What is claimed is:

1. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks.

2. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks, one of said blocks being identical with another of said blocks but having adifferent side uppermost.

3. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks, one of said blocks being identical with another of said blocks but having positioned uppermost the side which in said another block is lowermost. 55

4. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending across 5 said central portion from one edge thereof to the other.

5. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending diametrically acress said central portion.

6. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending from a point near the center of said central portion to its edges.

'7. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom, substantially throughout its periphery: said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending in six different directions from a point near the center of said central portion to its'edges.

8. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery, said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending in six different directions from a point near the center of said central portion to its edges, said lines forming substantially equal angles of intersection with one another.

9. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending from a point near'the center of said central portion at angles of approximately 120 from one another, whereby are formed three similar wedge-shaped sections.

10. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; the contacting surfaces of said blocks forming straight lines of cleavage extending from a point nearthe center of said central portion at angles of approximately 120 from one another, whereby are formed three similar wedge-shaped sections, each of said sections comprising a group of blocks wedge-shaped in horizontal section and arranged to form a vertical opening suitable for the passage of an electrode through said roof.

11. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion having a plurality of electrode openings therethrough comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; all or said blocks being of only three different shapes.

12. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion having a plurality of electrode openings therethrough comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; all of said blocks being of only three different shapes, one shape being substantially triangular in horizontal section, but having one vertex abbreviated and shaped to form a part of the wall surrounding an electrode open- 13. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion having a plurality of electrode openings therethrough comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; all of said blocks being of only three different shapes, one shape being substantially triangular in horizontal section but having one vertex abbreviated and shaped to form a part of the wall surrounding an elec trode opening, and the other shapes each including a. convex side'and being used only at the periphery of said central section.

14. A furnace roof comprising: abutments, an arch portion, and a central portion within said arch portion and receiving pressure therefrom substantially throughout its periphery; said central portion having a plurality of electrode openings therethrough comprising blocks having all of their contacting sides vertical and so arranged as to transmit the pressure of the arch to each of said blocks; all of said blocks being of only three different shapes, one shape being substantially triangular in horizontal section, but having one vertex abbreviated and shaped to form a part of the wall surrounding an electrode opening, blocks of this shape being used with opposite sides up.

15. A central roof section for electrode furnaces comprising: a plurality of segments defined by vertical side faces radiating from the vertical axis of the roof, one or more of said segments being provided with an opening to receive an electrode; an electrode-receiving segment being composed of substantially triangular blocks having vertical side faces radially related to the electrode opening and base faces presented for abutment, some against adjacent segments, and others against supporting members radially remote from the axis of the roof.

16. In a furnace roof construction, an annular arch portion, and a central portion surrounded by and in abutment with said arch portion; said central portion comprising a plurality of triangular sections each defined by a surface through which it abuts against the arch portion and two surfaces through which it abuts against the adjacent triangular sections, providing straight radial planes of cleavage extending from the 17. A furnace roof as described in claim 16. in which each triangular section is composed of a. plurality of triangular bricks abutting one against another through surfaces lying in planes 5 at large angles of incidence to the radial planes defining the sections; and certain oi! the abutting faces between bricks of one section are aligned with abutting feces between brick: of other sections and form slip lines o! oleame related as chords of the central portion on opposite sides of each diametric slip line.

HOWARD A. McPHERSON. 

